Hello, I got some problems when I simulated the strom surge using the Flow Flexible Mesh Model in Delft3D FM. The simulation is a warm start, inputting the initial water level of the grid, the wind data of a typhoon(spider web grid) and so on. The period of the simulation is the same as that of the wind data.
  When I got the results of the simulation, I was confused that the waveform of the storm surge is irregular and not smooth from 8-21 09:00:00 to 8-21 21:00:00(see the attachment below). I don't know why this phenomenon happened. Can anyone explain that? Many thanks.